Rock core drill head



Sept. 21,1937. J. H. HOWARD ET AL 2,093,607

ROCK CORE DRILL HEAD Filed Feb. 4, 1955 fI QZ 24 V 22 c 25 25 27 23 2a ,4 Trae/vEY Patented Sept. 21, 1937 v UNITED STATES PATENT OFFICE 2,093,607 ROCK CORE DRILL HEAD John H. Howard, Huntington Park, and Alfred C. Catland, Alhambra. Calit; said Catland assignor to Globe Oil Tools Company, Los Nietos,

alif., a corporation of California Application February 4, 1935, Serial No. 4,848 Claims. (01.255-72) This invention relates to well drilling tools and and application of the invention, throughout has particular reference to core drills employed which description reference is made to the acin the rotary method of well drilling. A general companylng drawing, in which: object of the invention is to provide a practical Fig. 1 is a side elevation of a core drill embodyefiicient core drill that is very long wearing. ing ahead whose cutters are formed and related 5 In well drills having roller cutters and particu- .as provided by the invention. Fig. 2 is an enlarly in rock core drills the thrust bearings or larged vertical detailed sectional view of the washers at the ends of the cutters are subjected to lower portion of the drill and the cutter head.

away from the wall of'the well bore or away from illustrating an outer cutterand its mounting. the core as the case may be, and as the wear Fig. 4 is a view similar to Fig. 3 illustrating an increases the drill rapidly loses gauge or drills an inner cutter and its mounting and F g. 5 is a undersized bore and core. When the wear of the bottom elevation of'the drill head.

thrust parts or washers of the cutter mountings The present invention is primarily concerned wears away and in some instances the cutter roller cutters of a well drill and is adapted to be assemblies are lost in the well. applied to or embodied in drills varying consid- Another object of the present invention is to erably in character- In 'the followin detailed provide a core drill head in which the cutters disclosure we will describe the invention as emare shaped and related so that they are braced bodied in th'ehead of a more or less typical core or supported to a substantial extent against drill, it being understood that the invention is the principal end thrusts by their contact with not to be construed as limited or restricted to the earth formation whereby the thrust bearing the specific form or application about to be departs. of their mountings are relieved of considscribed.

erable wear, making the tool long wearing and The core drill illustrated in the drawing incapable of drilling a bore to gauge for a maxieludes an Outer barrel W B' lifter Sub H connected with its upper end. Y A threaded pin Another object of the invention is to provide I2 is pr v d n the pp nd of he Sub H a core drill head that comprises a'plurality of tofacilitate the connection of the drill with a spaced inner and outer roller cutters that are drill collar or o h r p rt of n perating r n .shaped and related to form an annular ridge of A sub I3 on the lower end of the outer barrel in earth formation at the bottom of the well bore carries a bit head sub M. A pin l5 projects that is engaged by the inner ends of the cutm he owe end of the sub H to carry the nor to partially balance or compensate for the the W llh r a he I8 in lud s l s 9 principal heavy end'thrusts to which the cutters that are actuated inwardly to grip the core C are subjected thus relieving the thrust receiving by cooperating with the inclined lower wall of members of the cutter-mountings of considerthe opening H. The innerbarrel i6 is spaced able wear. from the interior of thefiouter barrel in leaving Another object of the invention is to provide an annular fluid passage 20. Spaced longitudia. core drill head of the character mentioned in ma] ports 2| are provided in the wall of the sub which the forming and cutting away of the H to carrythe circulation fluid downwardly from thrust compensating ridge of earth formation the passage 20 to the bit head. does not retard the drill or detract from its efii- The present invention includes, generally, a cient cutting action. tubular shoe or bit head body 22 and a plurality The various objects and features of our invenof inner cutters A and outer cutters B and B. tion will be fully understood from the following The shoeor body of the head is an annular or detailed description of a typical preferred form tubular member having a central longitudinal I5. A plurality of circumferentially spaced ribs or wings 25 is provided on the lower portion of the body 22. The spaces between the wings 25 constitute channels 26 for passing the upwardly flowing circulation fluid as it flows around the lower end of the body. Spaced sockets or recesses 21 and 28 are provided in the lower end of the body 22 to carry the cutters A and B and B. The recesses 21 and 28 are located so that the wings 25 constitute the body parts which form or define the outer walls of the recesses. The inner and outer walls of the recesses 21 are preferably inclined downwardly and inwardly with respect to the longitudinal axis of the drill. The inner and outer walls of the recesses 28 are preferably inclined downwardly and outwardly with respect to the axis of the tool. Bosses 29 are provided on the inner walls of the recesses 21 and the outer walls of the recesses 28. The invention contemplates the employment of various numbers of inner and outer cutters A, B and B. In the particular drill head illustrated there are two dia-. metrically opposite recesses 21 for carrying two cutters A and two pairs of recesses 28 spaced between the recesses 21 for carrying four cutters B and B. An annular groove 38 is provided in the upper end of the body 22 to register with the lower ends of the ports 2|. Spaced longitudinal ports or passages 3| extend through the wall of the body 22 from the groove 30 to the upper ends of the recesses 21 and 28 to discharge the circulation fluid downwardly against the cutters A, B and B, respectively.

The cutters A and B are rotatably supported or mounted in the recesses 21 and 28 to rotate about axes inclined relative to the axis of the drill and to project from the lower end of the head to act on the earth formation. In accordance with the broader aspects of the invention the cutters A, B and B may be rotatably supportsuitable manner. In the drawing we have illustrated the cutters A, B and B rotatably mounted or supported by the means fully described and claimed in our copending application entitled Core drill head, Serial No. 4,846, filed February 4, 1935, which has matured into Patent No. 2,058,15fr granted Oct. 20, 1936.

The cutter mounting means illustrated includes pins 28. One end of each pin 32 is threaded in an opening 33 in the body 22 and the opposite headed or enlarged ends of the pins are carriedin openings 34. Bushings 35 are provided on the pins 32. Each bushing 35 has a radially projecting annular flange 36 at one end to bear against the boss 29 on the wall of the recess. The openings of the bushings 35 where they pass through the flanges 36 have fiat walls 31.- The fiat walls 31 on the interiors of the bushings 35 cooperate with flat faces 38 on the pins 32 to hold the bushings against rotation. Thrust washers 39 are provided on the pins 32. The thrust washers 39 on the pins 32 carrying the inner cutters A bear against the outer walls of the recesses 21 while the washers 39 on. the pins 32 carrying the outer cutters B and B bear against the inner walls of the recesses 28. Roller bearings 40 are provided on the bushings 35 to rotatably support the cutters A, B and B.

The inner cutters A are provided to act on the earth formation to form the inner portion of the well bore and to trim the core C. The cutters A are in the nature of roller cutters that are and the ends 32 extending through the recesses 21 and substantially cylindrical in their general configuration. Each cutter A has a central longitudinal opening'4l provided at one end with an enlargement or socket 42. The inner cutters A are rotatably supported in the recesses 21 by the bearing means just described to rotate about axes inclined downwardly and outwardly relative to the longitudinal axis of the drill. The cutters A are arranged to be rotatably supported on the bushings 35 through the rollers or bearings 42. The flanges 36 on the bushings are received in the sockets 42 and the outer ends of the cutters A have thrust bearing cooperation with the washers 39. The cutters A mounted in this manner project downwardly beyond the lower end of the body 22 and project into the opening 33 to trim the core C.

The inner cutters A are provided with peripheral cutting teeth or cutting parts 43. The cutting parts 43 extend axially of the cutters and may be continuous. The cutting parts 43 are preferably spiralled and it is preferred to pitch the parts 43 of one cutter A in a right hand direction and the parts 43 of the other cutter A in a left hand direction. The inner ends or corners 44 of the cutting parts 43 are cut away or bevelled to properly and effectively trim the core C. The ends 44 of the cutting parts are substantially vertical when they come into contact with the earth formation to trim the core. The principal axial cutting edges of the parts 43 are inclined where they contact the earth formation to provide the bottom of the well bore with a downwardly and outwardly inclined wall portion 45.

In accordance with the invention the outer corners or ends 46 of the cutting parts 43 are cut away or bevelled wardly inclined edges or faces as they engage the earth formation. These ends 46 of the cutting parts cooperate with the earth formation to form a downwardly and inwardly inclined wall or surface 41 on the bottom of the well bore surrounding the surface 45. The ends 46 of the cutting parts 43 are inclined in the opposite direction to the principal longitudinal edges of the cutting parts and their engagement with the surface 41 of the earth formation balances and counteracts the outward end thrusts resulting the principal cutting edges 44 of the parts 43 with the formaof the ends 46 of the cutting 41 relieves the thrust from cooperation of tion. The contact parts with the surface washers 39 of a substantial amount of end thrusts to which they might otherwise be subjected.

The cutters B and B are the outer cutters for acting on the outer portion of the bottom of the well bore and for cutting the bore to size. The outer cutters B and B are substantially frustoconical roller cutters having flat oppositeends and inclined or tapered peripheries. cutter B and B has a central longitudinal opening 50 having a socket in its inner end. The cutters B and B are mounted on the pins 32 extending through the recesses 28 through the medium of the bushings 35 and bearings 40. The flanges 36 of the bushings 35 are received in the sockets 5|. The inner ends of the cutters B and B bear against the washers 39. In accordance with the invention the outer cutters B and are rotatable about downwardly and inwardly inclined axes. The pins 32 extending through the recesses 28 are inclined downwardly and inwardly to be substantially normal to the inner and outer walls of the recesses.

Each outer Y the formation at the outer surface of the of an appreciable provided on the outer cutters bore. The ends Axially extending teeth or cutting parts 53 are B and B. Each pair of adjacent outer cutters includes a cutter B having straight axial cutting parts 53 and a cutter B having spiralled cutting parts 53. spiralied cutting parts 53 of the opposite sides of the body pitched in opposite directions. cal cutters B and B downwardly and inwardly inclined axes have their cutting parts 53 and 53 substantially horizontal where they come into contact with the earth formation at the bottom of the bore to provide the bottom of the well bore with a substantially flat horizontal wall or surface 54.- The outer corners or ends of the cutting parts 53 and 53 are bevelled or pitched to properly cooperate with the formation at the side wall of the well 55 of the cutting parts are pitched to be substantially vertical when in active engagement with the side wall of the well bore. It'is a feature of the invention that the inner ends 55 of the cutting parts 53 and 53 are pitched or inclined to act on the earth formation and form a downwardly and outwardly inclined surface 51 at the bottom of the bore whose upper end'joins the surface 41 to form or leave an annular ridge R. ,The engagement of the ends 55 of the cutting parts B and B with the outer surface 5'! of the ridge R balances or counteracts the heavy inward thrusts put upon them by their engagement with the bottom and side walls of the well bore, thus relieving the washers 39 of these end thrusts.

During operation of the core drill the drilling string or operating string is rotated in the usual manner and fed downwardly so that the cutters A, B and B act on the'formation to drill the well bore and form the core 0. The inner cutters A project from the bottom of the body 22 so that their cutting parts 43 engage the formation at the bottom of the bore to cut away the formation at the surface 45. The inner ends 44 of the cutting parts 43 trim the core to pass into the opening 23 withthe proper clearance. The outer ends 45 of the cutting parts 43 act on the formation at the inner surface 41 of the ridge R. This engagement of the ends 46 with the surface 41 supports the inner-cutters A against the outwardly directed end thrusts to which they are subjected because of their engagement with the core and the formation at the surface 45. The outer cutters B and B project beyond the lower end of the body 22 so that their cutting parts 53 r The the cutters B at 22 are preferably The frusto-coniand 53 act on the'formation at the surface 54 to drill the outer portion of the well bore. The outer ends 55 of the outer cutters B and B engage the side wall of the bore and operateto cut the bore to the proper gauge. The inner ends 55 of, the cutting parts 53 and 53 engage ridge R. This engagement of the ends 55 with the surface 51 balances or compensates for the engagement of the ends 55 and the principal edges of the cutting parts 53 and 53* with the formation thus relieving the thrust washers 33 amount of end thrusts.

The sets of cutters A and the sets of cutters B and B are related and shaped to provide or leave the annular ridge R at the bottom of the well bore which constitutes a thrust ridge or abutment against which the ends of the cutting parts bear totrelieve the thrust parts of the cutter mountings'of end thrusts. The forming of the ridge R and the presence of the ridge R at. the

in being rotatable about bottom of the bore do not in any way interfere through the cooperation ofthe ends of the cutting parts with the ridge R are very long wearing to prevent end play or movement of the cutters.

The ridge R of earth formation materially aids in supporting the cutters so that the cutter mountings are capable of supporting the cutters in positions to drill the bore to the proper gauge and to drill the core C to size for a maximum length of bore or hole.

Having described only a typical form and application of our invention, we do not wish to be limited or restricted to the specific forms and applications herein set forth, but wish to reserve to ourselves any modifications or variations that may appear to those skilled in the art or fall within the scope of the following claims.

Having described our invention, we claim:

1. A well drill including a body, a cutter supported .on the body forfrotation and projecting from its lower end, cutting parts on the. cutter for acting on the formation at the bottom and side wall of the bore, and bevelled innenend faces on the cutting parts engaging the formation to support the cutter against the end thrusts imposed by its engagement with the bottom and side wall of the bore.

2. A core drill head including an annular body, a substantially frusto-conical cutter projecting from the lower end of the body and-rotatable about an axis inclined downwardly and inwardly relative to the longitudinal axis of the drill, .peripheral cutting parts on the cutter'for acting on the formation at the bottom wall of the bore, and beveled inner'end faces on the cutting parts pitched relative to both the inner end of the cutter and the longitudinal edges of the cutting parts for engaging the formation to support the cutter against inward thrusts.

3. A core drill head including an annular body, a substantially frusto-conical cutter projecting from the lower end of the body and rotatable against end thrusts about an axis inclined downwardly and inwardly outwardly relative to the inner end of the cutter for engaging the formation to counteract the inward thrusts on the cutter.

4. A core drill head including, a tubular body, a cutter projecting from the lower end of the body and supported thereon for rotation, peripheral cutting parts on the cutter having inner ends for trimming a core'for reception by the body, and relatively blunt outer end faces on the cutting parts pitched relative to the outer end of the cutter and the principal cutting edges of the cutting parts to be inclined downwardly and inwardly when they act on the formation to sup- Port the cutter against outward thrusts.

5. A core drill head including a tubular body,

'a substantially cylindrical cutterprojecting from the lower end of the body and rotatable about a downwardly and outwardly inclined axis, axially the cutter having incore for reception by parts to be inclined downwardly and inwardly relative to the longitudinal axis of the body as they come into engagement with the formation to support the cutter against outward thrusts.

6. A core drill head including a tubular body,

an outer cutter supported on the body for rota- I tion and projecting from the body to engage the formation at the bottom of the bore and to cut the bore to size, said outer cutter having inwardly facing cutting parts to act on a surface of the formation to counteract the inward thrusts on the cutter, and an inner cutter supported on the body for rotation and projecting from the body to engage the formation at the bottom of the bore and to trim a core for reception by the body and having outwardly facing cutting parts inclined downwardly and inwardly when they act on a surface of the formation and operable to counteract the outward thrusts on the inner cutter, said surfaces defining a ridge on the bottom of the bore.

7. A core drill head including a tubular body, an outer cutter supported on the body for rotation about a downwardly and inwardly inclined axis and projecting from the body to engage the formation at the bottom of the bore and to cut the bore to size, said outer cutter having inwardly facing cutting parts inclined relative to the inner end of the cutter and operable to act on a surface of the formation to counteract the inward thrusts on the cutter, and an inner cutter supported on the body for rotation about a downwardly and outwardly inclined axis and projecting from the body to engage the formation at the bottom of the bore and to trim a core and having outwardly facing cutting parts inclined downwardly and inwardly when they act on a surface of the formation and operable to counteract the outward thrusts on the inner cutter, said surfaces defining a ridge on the bottom and projecting from of the bore.

8. A core drill head including a tubular body, an outer cutter of substantially frusto-conical configuration supported on the body for rotation the body to engage the for reception by the body formation at the bottom of the bore and to cut the bore to size, said outer cutter having inwardly facing cutting parts inclined relative to the inner end of the cutter and operable to act on a surface of the formation to counteract the inward thrusts on the cutter, and. an inner cutter of substantially cylindrical configuration supported on the body for rotation and projecting from the body to engage the formation at the bottom of the bore and to trim acore for reception by the body and having outwardly facing cutting parts inclined downwardly and inwardly when they act on a surface of the formation and operable to counteract the outward thrusts on the inner cutter, said surfaces defining a ridge on the bottom of the bore.

9. A well drill including a body, a cutter supported on the body for rotation and projecting from its lower end, and cutting parts on the cutter having longitudinal cutting edges for acting on the formation at the bottom of the bore and that are substantially horizontal when in contact with the formation at the bottom of the bore, outer faces for acting on the side wall of the bore, and inner faces at the inner ends of the said longitudinal cutting edges inclined downwardly and outwardly relative to both the said longitudinal cutting edges and the inner end of the cutter when in contact with the formation to form and bear on a correspondingly inclined surface on the formation to support the cutter against inward thrusts.

10. A core drill head including, a tubular body, a cutter projecting from the lower end of the body and supported thereon for rotation, cutting faces on the inner end of the cutter for trimming a core for reception by the body, and cutting faces on the outer end of the cutter inclined downwardly and inwardly when they act on the formation and pitched at more than to the axis of rotation of the cutter to compensate for the end thrusts imposed on the cutter by the first mentioned cutting faces.

JOHN H. HOWARD. ALFRED C. CATLAND. 

